[Karmic] Surround volumes not equally distributed

Stereo is working fine, but surround gives me trouble (the same in jaunty ...). If I turn the sound volume to the lowest level, the front volume (called master in alsamixer) is very low, but the rear volume (called surround in alsamixer) is at ~80%. If I then turn the the volume slider even further down, both front and rear get muted.

If I turn the volume slider up, only front gets louder until it reaches about 20%, then suddenly the rear volume goes up to 100%.

LFE and Master are somewhat linked together. PCM acts nearly the same way as Surround, but its volumes doesn't get that high.

I tried to change the device settings to 5.1, 7.1 and all the other possible values. But most of them give me scratchy sound and some (even more) weird volume problems.

To sum it up: sound is working on all speakers, but the volume gain is unequally distributed among the speakers. First to surround speakers are too lound. At a certain volume level, they don't get any louder any more, but the front is too loud instead.

In Jaunty I finally managed to make the volume slider work correctly, by selecting those "output lines" (eg, master, front, rear) that should be adjusted by the volume slider. But in Karmic this preference applet is gone.

Re: [Karmic] Surround volumes not equally distributed

Nobody? Does anybody of you just have any clue or experience with this problem?
I search many forums and didn't find anything useful. I tried so many hints - edit config files or install additional apps, but couldn't resolve the problem.